Why won't it start?

[Traacer]

I bought a Craftsman FWD self propelled push mower with Briggs 6.5 engine. The gentleman I bought it from said he had just mowed with it a week earlier but it wouldn't start when I got there. The gas smells fresh and the primer bulb is definitely moving gas into the carb. The mower still won't start. No sputtering, popping, backfiring, nothing. It pulls good and feels like its getting plenty of compression. Here's what I've tried so far: Checked the sparkplug for spark, it's getting spark, the spark looks strong and the plug looks good. Took off the air cleaner and sprayed carb cleaner / starting fluid directly into the carb and pulled it, no love. Made sure the throttle linkage was working and was set on start. Checked to make sure the kill switch linkage was working. Made sure the self propelled wasn't engaged.

Anyone have any suggestions? Thanks!

 

[davbell22602]

Might also be stretched blade engine stop cable or bad coil.

 

[Traacer]

Might also be stretched blade engine stop cable or bad coil.

Already ruled out the cable. Don't know what a stretched blade is, explain? How do I check/rule out the coil? Thanks for the help.

 

[davbell22602]

How did you rule out a stretched blade/engine stop cable? To rule out a stretched engine stop cable. You clamp pilers on the lever and bracket that the cable is on then pull rope to see if it starts. If it starts just remove clamped pilers from lever


To test coil:


Remove spark plug, then put it in the spark plug boot, then hold up to a cylinder head cooling but not touching it. While doing that have someone else pull the cord 5-10 times then see if the spark plug sparks off the cylinder head cooling fin.

 

[MRCo.]

2 initial ideas:

1. New plug. Plugs can fire when out of the cylinder so you think they are good, but under compression they don't fire.

2. Sheered flywheel key. You have fire but it's not when the piston is tdc, so not enough compression when firing. Timing is off.

 

[Rivets]

Have you checked to see that the choke is closing all the way. Please post all the engine numbers, model, type and code.

 

[Traacer]

2 initial ideas:

1. New plug. Plugs can fire when out of the cylinder so you think they are good, but under compression they don't fire.

2. Sheered flywheel key. You have fire but it's not when the piston is tdc, so not enough compression when firing. Timing is off.

OK so here's an update. Put in new spark plug properly gapped. Still won't start. Drained gas (just in case). Visual inspection of carb and bowl. Looks ok, and getting gas. Sprayed carb cleaner into the carb and pulled, no start. Sprayed carb cleaner into the spark plug chamber, replaced plug and pulled, no start. Removed gas tank and engine cover. There was a LOT of old grass under the engine cover. Removed excess grass and cleaned things up. Visually confirmed that engine brake assembly was working properly. Haven't checked the flywheel key yet, that's next. Thanks again for your help... any new suggestions?

 

[reynoldston]

That's what I was going to say. Check the flywheel key. He might of hit something and it quit running so he sold it to you. I hope you didn't pay much for it not runing

 

[Traacer]

That's what I was going to say. Check the flywheel key. He might of hit something and it quit running so he sold it to you. I hope you didn't pay much for it not runing

Nah, only paid 20 bucks for it. I looked at the blade and it didn't look like it had any damage. I'm starting to think this one might be a dud but I'm going to check the flywheel key next just to see.